dbcve.org
Ios XrOperating system · Cisco

CVE-2018-15428

MEDIUM · 6.8 CVSS v3.0 Published 2018-10-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific, malformed attribute to be processed by an affected system. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP traffic only from explicitly defined peers. To exploit this vulnerability, the malicious BGP update message would need to come from a configured, valid BGP peer, or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A memory corruption or logic error in Cisco IOS XR's BGP implementation causes the BGP process to crash and restart when processing BGP update messages containing a specific malformed attribute. This results in a denial of service. Exploitation requires the attacker to send the malicious BGP update from a configured, valid BGP peer or to inject it into an existing TCP session with a BGP peer.

MitigationApply the Cisco IOS XR software update when available. Additionally, implement BGP route authentication (MD5 or TCP-AO) and ingress filtering to validate that BGP messages originate from authorized peers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ios XrOperating system
Affected:= 6.0.1= 6.0.2= 6.1.1= 6.1.2= 6.1.3= 6.1.4= 6.2.1= 6.2.2= 6.2.3= 6.4.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Cisco IOS XR version
    Run 'show version' or 'admin show version' on the device to display the installed IOS XR software version.
    Affected if The installed version matches one of the affected versions: 6.0.1, 6.0.2, 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.2.1, 6.2.2, 6.2.3, or 6.4.1.
  2. Confirm BGP is configured
    Run 'show bgp summary' or 'show running-config | include router bgp' to check if BGP is enabled and configured on the device.
    Affected if BGP is actively configured and running on the IOS XR device.
  3. Check for configured BGP peers
    Run 'show bgp neighbor' to display configured BGP peers. The vulnerability requires the malicious update to originate from a valid, configured BGP peer or an injected TCP session with a BGP peer.
    Affected if Any BGP peers are configured and actively exchanging updates.
  4. Review recent BGP process restarts
    Run 'show log' or 'show process bgp' to examine logs for unexpected BGP process crashes or restarts that may indicate exploitation.
    Affected if Unexplained BGP process crashes or restarts are observed in the logs.

You are affected if the device runs a matching IOS XR version (6.0.1 through 6.4.1) and has BGP configured with active peers, as the vulnerability triggers upon processing a malformed BGP update from a peer.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco IOS XR software update when available. Additionally, implement BGP route authentication (MD5 or TCP-AO) and ingress filtering to validate that BGP messages originate from authorized peers.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-15428 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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